Yahoo! News - Brain Rewards Us for Laughing: Study
Humor is no laughing matter, according to Dr. Allan L. Reiss of Stanford University in California, who led the research.

"Humor has significant ramifications for our psychological and physical health," he told Reuters Health. Our sense of humor, he said, "often dictates if, how and with whom we establish friendships and even long-lasting romantic relationships." Humor is also a "universal coping mechanism" for dealing with stress, Reiss added. Despite the importance of humor, Reiss said that little is known about the brain mechanisms that underlie humor.

Researchers found that when a cartoon made a person laugh, a brain network that is known to be involved in reward was activated. In fact, the areas activated by humor have been shown previously to be activated by amphetamines and cocaine, according to a report in the December 4th issue of the journal Neuron.

Hmmmm, very interesting....